Biodegradation of PET: Current Status and Application Aspects

TLDR

PET is a chemically inert, microbe‑resistant plastic whose widespread accumulation causes microplastic pollution, and bioremediation offers a potential alternative to recycling. The study introduces PET‑degrading microorganisms and enzymes, and traces the evolution of PET hydrolytic enzymes to overcome barriers to microbial and enzymatic PET degradation. The paper discusses potential applications of PET degradation. PET hydrolytic enzymes have been identified and PET degradation demonstrated by a microbial consortium and *Ideonella sakaiensis*, with the enzymatic mechanism clarified but low catalytic activity indicating the need for further development for commercialization.

Abstract

Most petroleum-derived plastics, as exemplified by poly(ethylene terephthalate) (PET), are chemically inactive and highly resistant to microbial attack. The accumulation of plastic waste results in environmental pollution and threatens ecosystems, referred to as the "microplastic issue". Recently, PET hydrolytic enzymes (PHEs) have been identified and we reported PET degradation by a microbial consortium and its bacterial resident, Ideonella sakaiensis. Bioremediation may thus provide an alternative solution to recycling plastic waste. The mechanism of PET degradation into benign monomers by PET hydrolase and mono(2-hydroxyethyl) terephthalic acid (MHET) hydrolase from I. sakaiensis has been elucidated; nevertheless, biodegradation may require additional development for commercialization owing to the low catalytic activity of these enzymes. Here, we introduce PET degrading microorganisms and the enzymes involved, along with the evolution of PHEs to address the issues that hamper microbial and enzymatic PET degradation. Potential applications of PET degradation are also discussed.